Wine filtration step by step: from coarse filtration to the filler

Step-by-step wine filtration spreads the load across several cartridges: each stage retains something different—coarse solids, turbidity, colloids, yeasts, and bacteria—and protects the next one. That way, the membrane that microbially stabilizes the wine before the filler receives only what no earlier stage can retain; it lasts longer, and the cost per bottled liter goes down.

A complete filtration train has four stages: coarse filtration, clarification, final filter protection, and final filtration. Around them are the housings, the membrane integrity test, and the sanitization that allows the cartridges to be reused between batches. Which stages are needed, and at what rating, depends on the wine, on the condition in which it reaches filtration, and on what has to be retained.

The stages of wine filtration

Stage	What it retains	Medium	Models
Coarse filtration	Coarse solids	304 stainless steel mesh	MicroMesh
Clarification	Particles, turbidity, and colloids	Pleated polypropylene · glass microfiber	ProFlow Plus, ProFlow, and ProFlow Protec · MicroFiber Max and MicroFiber Plus
Final filter protection	The fine load that would plug the final membrane	Depth medium + PES membrane · 0.65 µm PES membrane	PreFiber GF + PES, PreFiber Max GF + PES, and PreFiber A PP + PES · LifePure W
Final filtration	Yeasts and bacteria	PES or nylon 6,6 membrane	LifePure Plus F&B, LifePure, and LifePure F&B · UltraPure F&B and UltraPure Plus F&B

SaniFlow housings hold the cartridges for each stage. We cover them at the end, together with integrity testing and sanitization.

Coarse filtration: the first barrier

If the wine arrives carrying coarse solids, it pays to remove them before they reach finer cartridges. The MicroMesh is a pleated 304 stainless steel mesh cartridge, available in 12, 20, 40, 100, 200, and 500 µm, for coarse clarification. The mesh and the polypropylene components are thermally bonded, with no glues or adhesives, which is why its catalog declares it suitable for contact with food and beverages.

Its advantage at this stage is that it withstands repeated cleaning: it is washed and goes back into the line. In single-open-end cartridges with an internal reinforcement, it tolerates hot water at 80 °C, peracetic acid and sodium hydroxide up to 1%, and steam at 121 °C.

Clarification: pleated polypropylene and glass microfiber

Clarification lowers turbidity and retains particles and colloids ahead of the membrane cartridges.

Pleated polypropylene. The ProFlow Plus comes in ratings from 0.2 to 40 µm, with an absolute rating declared for the 0.5 to 20 µm grades (99.9%, Beta 1000), and 8,000 cm² of filtration area per 10″. It is 100% polypropylene, with no additives or surfactants and low levels of extractables. For wines with a heavier load there are dual-layer versions: ProFlow, from 0.45 to 3 µm, and ProFlow Protec, with absolute ratings from 0.2 to 10 µm. They combine a prefilter and a final layer in the same element and take longer to reach the change-out pressure. All three include wine among their applications.

Glass microfiber. The MicroFiber Max combines a high-density glass prefilter with a final retention layer, in 0.45, 0.65, and 1.2 µm: it captures colloids and fine particles progressively and is designed as a prefilter for 0.2 and 0.45 µm membranes. The MicroFiber Plus, with graded density and 0.8 m² per 10″, covers 0.45 to 40 µm and names wine prefiltration among its uses. Both are 100% thermally bonded, with no adhesives.

Protecting the final filter

Between clarification and the final membrane, a prefilter should take up the fine load the wine still carries. That is the job of the PreFiber hybrids, which combine a depth medium and a PES membrane in the same cartridge:

• PreFiber GF + PES: high-capacity glass microfiber + asymmetric PES, with 6,700 cm² per 10″ and low pressure drop. Its catalog specifies it for filtration ahead of final membranes in wine.
• PreFiber Max GF + PES: high-density glass microfiber + asymmetric PES, for heavy particle and colloid loads. It lists wine clarification among its applications.
• PreFiber A PP + PES: pleated polypropylene depth medium + PES, with absolute ratings from 0.1 to 1.2 µm. It also includes wine.

The other option is a 0.65 µm membrane upstream of the final one. The LifePure W (LifePure W series) is a single-layer PES membrane that retains more than 10⁷ Saccharomyces cerevisiae per cm², with 8,000 cm² per 10″. Its catalog specifies it as a final filter before bottling or as an integrity-testable prefilter.

To choose among these options, the same rule applies as for any prefiltration: the load should be shared, and the stages should reach their change-out ΔP at similar times. We go into this in prefiltration: how to protect the final filter.

Final filtration before the filler

The last stage microbially stabilizes the wine before filling: it retains the yeasts and bacteria that could spoil it in the bottle. It is done with membranes in two materials:

• Asymmetric polyethersulfone (PES), with open pores on the outer face that narrow down to the final pore: LifePure Plus F&B, with 8,000 cm² per 10″, and LifePure and LifePure F&B, with 6,000 cm².
• Nylon 6,6, a naturally hydrophilic membrane: UltraPure F&B, with 8,000 cm² per 10″, and UltraPure Plus F&B, with 9,500 cm².

The catalogs declare the retention of each rating against a challenge microorganism:

Rating	Microorganism	Declared retention	Models
0.1 µm	Acholeplasma laidlawii	> 10⁴/cm²	LifePure · UltraPure F&B and UltraPure Plus F&B
0.2 µm	Brevundimonas diminuta	> 10⁷/cm²	LifePure Plus F&B, LifePure, and LifePure F&B · UltraPure F&B and UltraPure Plus F&B
0.45 µm	Serratia marcescens	> 10⁷/cm²	LifePure Plus F&B, LifePure, and LifePure F&B · UltraPure F&B and UltraPure Plus F&B
0.65 µm	Saccharomyces cerevisiae	> 10⁷/cm²	LifePure Plus F&B, LifePure, and LifePure F&B · UltraPure F&B and UltraPure Plus F&B

The 0.2 µm retention of B. diminuta matches the FDA definition of a sterilizing-grade filter; in the LifePure and both UltraPure models, the 0.1 µm rating declares it as well. Which rating to use depends on the wine, its load, and what needs to be retained: we define it with each winery.

Housings for each stage

• SaniFlow STE-01: AISI 304 sanitary housing for one 2 1/2″ cartridge with double 226 or 222 O-rings (configurations B to E), from 10″ to 40″. Surfaces and welds polished to Ra ≤ 0.8 µm, −1 to 10 bar and −10 to 150 °C, with 1 1/2″ clamp or 44.5 mm Fafeur connections. It complies with 3-A sanitary standards.
• SaniFlow STE-X: AISI 304 multi-element housing for 3, 6, 9, 12, 16, 22, 24, or 36 cartridges from 10″ to 40″, with the interior polished to Ra ≤ 0.8 µm, up to 10 bar, suitable for CIP and SIP, and with every housing hydrostatically tested. Its catalog specifies it for wine prefiltration and final filtration.
• SaniFlow STE-DO: AISI 316L, for one double open end (DOE) cartridge, up to 7 bar and 90 °C. It is used for process filtration of wines, syrups, and liqueurs where no positive seal is needed between the dirty side and the clean side.

In final filtration that seal is required: the membrane goes into a sanitary housing with double O-ring cartridges, such as the STE-01 or the STE-X.

Integrity, sanitization, and reuse

The integrity test confirms that the final membrane is intact and properly seated before the wine is entrusted to it. It is performed with the membrane wetted, by bubble point or by diffusive flow, and should be repeated before and after each final filtration. What each catalog declares:

• LifePure Plus F&B: 100% of the cartridges are integrity tested at the plant, and the model has diffusive flow and bubble point values so the winery can test it.
• UltraPure F&B and UltraPure Plus F&B: 100% of the cartridges integrity tested at the plant and verified at origin by diffusive flow, with diffusive flow and bubble point values for the user.
• LifePure F&B: integrity verified at origin by diffusive flow. LifePure W: integrity tested at the plant.

How these tests are run and how to read them is explained in filter integrity testing: bubble point and diffusive flow.

The LifePure and UltraPure membranes in this article withstand multiple 30- to 60-minute cycles with hot water at 80 °C, peracetic acid or sodium hydroxide up to 1% (10,000 ppm), and steam at 121 °C, in line or in an autoclave, and their catalogs declare them reusable. Steam and hot water are indicated for single-open-end cartridges (configurations B to E). On the housing side, the STE-X is designed for clean-in-place and steam-in-place (CIP and SIP).

How we help you build the filtration train

We make the prefilters, final filters, and housings in Argentina. The membrane cartridges are made in an ISO 7 cleanroom. Tell us the type of wine, the volume per batch, the flow rate, and the condition in which the wine reaches filtration, and we will propose the stages, ratings, and housings. The complete line by stage is on the winery filtration page; for your specific case, contact us with your winery’s details.